As communication technology is developed, portable terminals (e.g., smart phones, tablet PCs, and the like) are being widespread. The portable terminal provides an integrated user's function by adding various functions besides a voice call, a text call, and an image call service. Recently, advances in a portable terminal equipped with a touch screen are being developed. The portable terminal equipped with the touch screen is an input device as well as a display device performing an input and a display of the information in one screen.
Some portable terminals provide a pen such as a stylus pen as an input tool besides a touch using a user's finger. In operating the portable terminal, the user may use the more detailed touch by using a pen input means. Using a touch pen, a user may select and operate a specific area of a display unit which supports for a touch function more delicately since the pen has a pen tip which is sharper than a finger. Therefore, a method of increasing the user's convenience is developed by providing more various functions by using the touch pen.